No it's really not. And any sensible parent doesn't defer their child solely because they are summer born. You have to assess a range of factors and decide if it is the best and most supportive thing for the child in question. Deferring simply because they are summer born is never the right thing to do.
Errr... yes it is. It's clearly set out in the Code that there doesn't need to be a "problem" or specific reason to do it other than the child being summerborn. The entire point is that the data shows that for the majority of children starting school that young is detrimental, and has a measureable impact over their entire life. Hence the changes being introduced to be comparable to Scotland where deferral has been an option in place for decades successfully. And the many Scottish teachers on the thread saying people who defer very rarely regret it but many who don't defer do regret it. Some kids may be fine if not deferred. No way to compare to how they'd have been individually if they were though. The data is very clear that the impacts of early starts are largely negative, so of course it's reasonable for people to decide not to needlessly make their children's lives harder and expose them to additional mental health risks or risks of not achieving their full potential when they don't have to. Why would they do that?
If making a rational choice you've have to have extremely compelling reasons that the data didn't apply to your specific child to decide to send them early before compulsory school age now that you're not forced to do that or make them miss reception, rather than need a compelling reason to wait until they are. And given that it's not possible to predict with any child how they will progress academically, socially or in terms of mental health etc when they are 4, I think it's pretty clear that saying "they seem fine and ready for reception now" doesn't fulfil that. Most kids could cope with reception at 4, the problems proved to be associated with an early start at just turned 4 show up later. And you have no idea if they will for your child or not, no matter how confident or advanced they are at 4. Anybody making that decision is taking a huge unnecessary gamble on their child's wellbeing when they don't have to. Which is their right to do, of course. But far, far more risky given all the evidence we have than giving them more time and letting them start school when it is developmentally appropriate and less likely to cause them issues later on.
That's the whole reason for the policy, to provide a way to mitigate problem - the detrimental impact caused on the youngest children starting school in the UK because it starts school 2 years before most successful education systems - that is undeniably proved by the quantity of data now available from research on the topic. And to do so without the Government having to spend huge amounts of money to change the entire system to a more sensible one with children starting at 6 or 7 where this would be a non-issue, which would be a better solution and make deferral rules unnecessary, but they're not likely to do that so at least parents now have the option to choose. In the face of all the evidence I find it astonishing that anybody is complaining the option is there, telling people that they shouldn't do it based on anecdata from one or two random experiences they know of, or even claiming that it is wrong the option exists.
My mind boggles when people refuse to accept data as a good reason for decision making and seem to genuinely believe that their own limited perceptions and experiences as an individual will be a better guide to decision making, not just for themselves but also for others. Really odd.